Abstract: A hydrodynamic power transmission unit is constructed with cylindrical bearings positioned in the annular space between the outer hollow driver shaft and the concentrically disposed inner driven shaft and flow channels are provided to not only supply lubricating oil to the cylindrical bearings independently of the drive fluid supplied to the impeller and turbine discs but also to remove the spent lubricating oil in a way that it does not mix with the drive fluid. The resultant transmission unit, which can be used as a clutch for driving the cooling fan of an internal combustion engine, is more reliable and less expensive than prior art transmission units, and less noisy.

Abstract: A reciprocating piston internal combustion engine having a plurality of heads, a glow plug associated with each one of the pistons, a source of DC voltage, and a control for providing heating power to the glow plugs. The engine also has engine oil and transmission oil flowing therethrough, and a fan for cooling the oil. A first switch turns the fan on and off. There is included a central electronic control which includes thermistors for sensing a temperature related to the temperature of the engine and for providing a connection from the source of DC voltage to the glow plugs when the sensed temperature is below a predetermined value and for disconnecting the source when the sensed temperature is above the predetermined value. A duty cycle rate generator alternately connects and disconnects the source of DC voltage to the glow plugs above the preset value at a duty cycle rate which ranges from 0 to 100 percent and which depends on the voltage level of the source of DC voltage.